Key coicpajsty



Reissued 00h 11, 1921.

/Jsa

IF. MLLER.

CUTTER GRINDING MACHINE APruc/mou mn uw a. |921. y

Beissned out. 11, 1921. f 15,206.

4` SHEETS-SHEET 2- F. MULLER.Y CUTTER GRINDING NIAIHINE. APPLICATION FILED MAY3,192|

SHEEl-zgo'.

Reissued Oct. 11, 1921.

F. MLLER.

CUTTER GRINDING MACHINE.

APPLICATION msn 1M/3.1921.

Reissued Det. 11, 1921.

UNITED STATES PATENT ori-uca.

rnrnnnmcn ILLEE, or HARTFORD, CONNECTICUT, AssIoNoa To PRATT a wnrrl NEY COMPANY, or NEW YoEx, N. Y., A CoEroEATroN or NEW JEEsEY.

CUTTER-GRINDING MACHINE.

Original No. 1,338,320, dated April 27, 1820, Serial No. 253,871, illed September 13, 1918. Application for reissue led May, 3, 1921. Serial No. 466,594.

To all whom z't may concern1 Be it known that vI, FRIEDERICH MLLER, a citizen of the United States, residing at Hartford, in the county ofHartford and State of Connecticut, have invented certain new and useful Improvements in Cutter- Grinding Machines, of which the following is a specification.

A machine embodyingthe invention is particularly adapted for grinding the front radial or approximately radial faces of milling cutters and other analogous tools such as taps and reamers. The machine is primarily intended for the rinding of cutters having teeth with incliner? or helicoidal front' cutting faces, but the machine is not limited to such use and is e ually wel] adapted for grinding cutters having teeth with straight cutting faces parallel with thecutter axes. The machine can also be used for grinding the external or peripheral faces of cutter teeth.

One of the objects of the invention is t0 provide an impr ved cutter grinding machine in which rse is made of a grinding wheel having a conical grinding face, adapted to have line contact with the radial tooth faces. The cutters to be ground can have either plane or helicoidal cutting faces, and i either. cage the 4machine can be readily adjusted to accommodate cutters of differthe other ent diameters without interfering with the correct operative relationship between the 'ndin wheel and the cutters. Another Aolo- )ect of t e invention is to provideimproved means for holding and turning the cutters and for effecting adjustments to conform to cutters havin different degrees of inclination. A furt er object of the invention is to provide a wheel dressing mechanism having a novel relationship to the wheel and to arts ofthe machine which enables vthe wheelpto be'dressed without changin the eective grinding positionv thereo Further. objects of the invention are'to se-A cure Certain improved features of lconstruction and arrangement of parts which -wlll fication an claims. v

`In the acgmmpanying drawings I- have shown th embodiment of the invention be fully apparent from the following speciwhich is w deemed referable, butfit'willy l be'V understood that t e drawings are for illustrative purposes only and' are not to/be peripheral faces of cutter teeth.

cutting faces cannet ce ground construed as defining or limiting the scope A ofl the invention, the claims appended to 0f the drawings:

Figure 1 is a side view of a machine embodying the invention.

Fig. 2 is a front view.

Fig. 3 is a. plan view with the table and associated parts swung to a position different from that indicated in Figs. 1 and 2.

Fig. 4 is a fragmentary vertical sectional vlew taken along the line 4-4of Fig. 2.

Fig. 5 isa fragmentary vvertical sectional View taken along the line 5-5 of Fig. 3. y'

Fig/6 is a fragmentary vertical sectional view taken along the line 6-6 of Fig. 3.

Fig. 7 is a fragmentary7 vertical sectional view taken along the line f4-7 of Fig. 3, the crank being omitted.

Fig. 8 is a fragmentary vertical sectional view taken along the line 8-8 of Fig. 6.

Fig. 9 is a fragmentary vertical sectional view taken along the line 9-9 of Fig. 6.

Fig. 10 is a fragmentary vertical sectional Specilloation of Reissued Letters latent. Reissued Oct. 11, 1921A` View taken along the line 10-10 of Fig. 3. e0`

Fig. .11 is a plan view showing the gage for setting the dressing tool.

Fig. 12 is a fragmentary view Q Fpartly in section along the line 12-12 of Fig. 13 is a fragmentary side view partly 85 in section showing adifl'erent adjustment of the machine.

Figi. 14 is a fragmentary side view show#n ing t e machine arranged for grinding theff The machine is adapted for grinding out#A ters, particularly those requirlng grinding?` on the lfront cutting faces of their teeth.

`While isuitable for all 'kinds of cutters of this class it is especially useful for cutters with teeth havinghelicoidal frontcuttin faces. Obviously, these warped nelicodaf la; a'lw'lieel' having s: plane grinding face. h v`wheel must all radial lines being inclined with 'respect t0 the 'wheel axis. If the helicoidal cutting faces of a cuttter are radial, as will be a's- '-sumed, the cutter to be ground. must be held in such' aposition that'its axis will intersect 10a' the line fof Contact between the wheel and the face being ground. The cutters will vaiy considerably in diameter, and relativea ave a grinding face which is conical, 1001 justment must accordingly be effected between the wheel and cutter holder. In accordance with the invention, this adjustment is effected along lines which are inclined with respect to the Wheel axis and which are parallel with the conical surface of the wheel at the line of engagement with the tooth faces. 0n account of this adjustment along inclined lines it is possible to change the position of the cutter holder Without interfering with the proper relationship i the cutter axis and to the wheel axis interbetween the grinding wheel and the cutter axls. A 1 v The grinding wheel is preferably adjustable longitudinally of its axis/,so as to maintain the aforesaid intersection notwithstanding changes in the wheel surface as the result of dressing. Preferably there is provided in combination with the partsabove referred to, a wheel dressing toobwhich is movable along a normally fixed line, the aforesaid adjustment of the wheel serving to bring it arranged at an angle to the wheel axis and this angle must vary with the degree of inclination of the cutting faces. l therefbrc provide means whereby the cutter holder can be angularly adjusted about a pivotal axis which preferably is perpendiculzn"to secting both of them.` It is therefore possi-- ble to adjust the cutter holder angularly without disturbing the before mentioned rellation of the cutter axis and the line of'engagement of the Wheel with the cutter faces.

The grinding wheelis indicated at l, this wheel being mounted on a' rotatable spinnic 2 driven by a belt pulley il. 'lhc spindle 2 is carried by suitable bearings -l and 5 mounted onthe main frame (if of lthe machine. The grinding wheel 1 has a grinding face 1L which slightly convex and' conical in forni.y all axial lines of the face being iruflincdwith respect to the wheel` axis. conical grinding face such as the facc i" is'ncccssary in orde-r to enable the wheel to have. line contact with the warped helicoidal front faces ol the teeth. lf the grii'iding facc were plano instead of con-ical itoliviously would not have liuc contact with the warped front 'Faces but would tend to intcrscct lhcm ami thus mnlilatc and destroy them. 'l'hc cxact angle ol the cutting face lwill dcpcnd to some cxtenl on the pitchl ofthe hclicoid'al cutting faces to bc groundbut For ordinary practice ananglc'of about 120, as shown, is satisfaclrcfcrably the whccl has` u second lfrcy ll which is also convex and conical 'u form.

The two faces mcct at the periphcvl "e forming parts of the rnttcr holder.

of the wheel, thus providing a narrow periphery which enables the wheel to enter the narrow grooves bet-Ween the teeth of cutters.

T here is provided a cutter holder T which is adapted to hold la cutter A in the position indicated in F ig. 5 and to present the faces ofthe teeth successively to the wheel for grinding. The cutter holder 7 holds the cut ter A in a position such that the axis of the cutter intersect the lineof contact between the face l and the tooth face being ground. In this way the` faces of the teeth are ground radial throughout. Relative adjustment can be effected between the cutter holder and the wheel in order to accommodate cutters of different diameters. This relative adjustment is effected in the direction indicated in Fig. 5; that is, along lines parallel with the grinding face la of the wheel. As before stated, the face l is coni nl, the line of grinding contactbeing inclined with respect to the wheel axis. The relative adjustment therefore takes place along lines inclined with respect `to the wheel axis and the result is that the line of grinding always intersects the axis of the cutter irrespective of the cutf4 ter diameter.

As illustrated, thc axis of the wheel l and of the spindle 2 is horizontal and the line of movementof the cutter holder is inclined; `and the wheel and its spindle are normally ,fixed against bodily movement and relative adjustment is effected by .bodily moving the cutter holder. This construction is preferable for various reasons, but it may be modified without departing from the spirit of the invention in its broader phases.

In the preferred embodiment of the in vent-ion there is provided a knee' 8 which isv movable along an inclined slide l) on the main framer.' The angle of inclination of the'sllide 9 is the same as that of the grinding face 1*l of the grimling wheel. Rotatably mounted inga bearing in the knee is a horizontal shaft having a hand wheel l0 at its outer-*emi and a bevel gear ll at its inner cnd. The bevel gear ll. mcshcs with a bevel `gear at thc upper end of an adjusting 'sc.rcwll. The end of thc scrcw lits a hearing in thc knee and the lower threaded end of the sci-cw engages a` uut or threaded boss Ill.- on thc main frame.V By means of thc hand wheel the screw lil can bc turned, thus raising or lowering thc knee, the kncc Inoving along inclined lines as hclore stated. After adjustment', the knee can be lockcd by means of a gib controlled by a handle 1,5;

ln Fig. (i thc cutter A is shown as being .a thrcadi-.ulting hoh, lult it will be understood that a `cutter of this typc has been sclcctod rncrcly by way oi' illustration and that any lorm ol' cutter may bc ground. 'lhc cutter is mounted on an arbor ll which is mounted bctwccn live and dcadccnlcrsl lo and li' The y dead center 17 is carried b y a T-,slot 23 into which extend 'I'bo live center 16 is carried b a controlling and indexing head 18 mounte on a table 19. The a tailstock which is also mounted on t e table 19 and which is adjustable longitudinally thereof alon a suitable guideway 20". A handle 20 is provided for locking the tailstock in adjusted osition.

The tagle 19y is supported on the knee 8 and is angularly adjustable with respect to th knee about a vertical axis which intersects the axis of the cutter and which also intersects the axis of the grindin wheel. In order thatcertain necessary or desirable changes and adjustments may be` effected, the table 19 is not directly pivotd to the knee 8 but is connected to certain interme` diste arts now to be described. The table 19 is lbngitudinally slidably mounted on a saddle 21 which in turn is adjustably secured to a carriage 22. Thecarria. e 22 has m24, 24 e aging the-saddle 21. VBy means of these bots the saddle can be connected to the carrie e at any desired position. The carriage is longitudinally slidably mounted on a turntable 25 which is pivtall mounted on the knee 8, being connected therewith by means of 'a pivot bolt 26. The turntable 25 can be secured in angularly adjusted position b means of bolts 27, 27.

For movin t e carriage 22 longitudinally along t e turntable 25, there 1s pro-A vided a longitudinal rack 28 secured to the 4 permitting carriage, and a' spur gear 29 meshin with the rack and mounted on a horizonta shaft 80. The shaft is carried by suitable bear ings on the turntable and it may be turned. b a suitable crank which is n ot shown. Byy turnin the shaft 30 together with;the gear 29, t e carriage 22 may be moved as required. The carrla e 22 can be held in its adjusted position wit respect to the turntable by means of a 'b 31 controlled by a screw 32 and a. han le 33. The screw 32 extends through a slot 34 in the knee, thus the turntable to be adjusted angularly. y

In order that the table 19 may be easily moved forward and backward longitudinally to carry the cutter past the grinding wheel and th'us effect grinding of the successive teeth, the following mechanism is provided The table 19 carries a rack 35 which engaged by a spur gear 36. Thisgear if mounted on a short transverse shaft 37 which is rotatably mounted on the saddle 21 and which carries a crank 38. It will be seen that by turnin this crank the op erator can move theta le 19 forward and backward as desired. The saddle 21 is provided at its rear side with a T-slot 3,9 by means of which two stops 40 are secured in lace, only one such stopbeing shown in t e drawing. These fstops adjustably,

adapted to be engafred by a lug 41 on the table thus limiting the extent of table movement.

When the cutter to be ground has inclined helicoidal cutting faces, as shown7 the turntable 25 together with the parts curried thereby must be turned to an ,angle corresponding to the angle of inclination of the cutting faces. These parts are shown so turned in Fig.x3. It will be noted that, inasmuch as the vertical pivotal axis of the turntable intersects the axis ot' the cutter,` the turning movement does not disturb the relationship between the cutter axis and the line of grinding contact on the wheel This line continues to intersect the cutter axis, thus remaining in position to grind the cutting faces radially.

i s the cutter is moved longitudinally to effect grinding, it must obviously be simultaneously turned in order to maintain con-.

tact with the grinding wheel. The rate of turning must be exactly proportional to the rate of 'longitudinal movement und must further more be in exact accord with the angle of inclination of the cutting faces. For eifecting'this turning movement the following lmechanism is provided. A longitudinal rack 42 is carrled by the saddle 21 and this rack is engaged by a spur gear 43. The gear 43 is secured to a transverse horizontal shaft 44 rotatably mounted in the head 18. Atthe outer rear end of the shaftv 44 is a gear 45 which meshes with a gear 46 on a secondtransverse horizontal shaft 47. The shaft 47 carries at its front end a gear 48. A third transverse horizontal shaft 49 is mounted in the head 18. This shaft carries at its inner end a bevel gear 50 and at its outer end a spur gear 51. The bevel gear 50 meshes with a bevel gear 52 on a'longitudinal spindle 53, the spindle 53 carrying the aforesaid center 16. Interposed between the Vgears 48 and 51 are two meshing idler gears 54 and 55. are carried by a plate 56 which is adjustable, being held by a bolt 5'7'which enters a slot 58 in the side of the head. It will be seen that when the table 19 is moved the gear 43 will roll along the rack 42 and thus e given a rotative 'movement This ro tative movement will be transmitted through the gears and 46, through the shaft 47, through the gears 48, through the shaft 49 to the bevel gearig5Q." From the bevel gear the motion is transmitlted to .the bevel gear 52 and thence to the spindle 53. The spindle 58 is rovided with 'a clamp 59 which is adapte to en age a d og C secured to the arbor In th s way the rotative movement of the Es indle is These gears 4 54. 55, and 51 and vtransmitted to the arborand to 't e cutter. 1 i

91 ditferentja fof.' inclination pf the the cutter 'must' be changed i180 tion normally as shown by dotted lines in Fig. 1. In order that this may be done, the 'bracket 79 is mounted on a pivot bolt 84 so that the bracket with the slide 81 and the tool 8() may be swung backward and upward. For holding the bracket in the o rative position there is provided a screw fiieiving a knurled head 85. When the screw has been withdrawn the bracket can be swung upward, ,the movement being limited by means of a stolp 86.

t has already been stated that the dressing tool is normally movable along a fixed line. In order that the tool maybe pre* lminarily adjusted to t-his fixed line and in order that it may be further adjusted to compensate for wear, it is mounted on a slide 87, this-slide carrying the pivotbolt 84 and the stop86. The slide 87 is horizontally adjustable with respect to the main frame 6, being movable under the control of a screw4 88. through slots in the slide serve to lock it in ad'usted position. y

or the assistance of the operator in adjusting the dressing tool to the aforesaid fixed line,I preferably provide gaging devices such as are shown in Figs. 11 and 12.

. There isrfurnished a gage 89l made of metal and havin the same shapeV as the grinding wheel, at Emst as concerns the conical surface 89" thereof.l This gage isput in place on the spindle approximately in the osioccupied by the whee as illustrated in Fig. 11. As a matter of -convenienee the dressin mechanism may be swt* uf to the position indicated in Fig. 12. he turntable 25 is adjusted to bring 'theorie of the two centers 16 and 17 at right Jangles to the spindle axis, asv illustrated. There is rovided a gage velement 89c which is in' the orm of avshaft or pin adapted to be mounted on the centers 16 and 17. This shaft or pin 89c is provided with a notch near its center which has a plane bottom surface assing through the axis. A bar 89d ,is provi ed which has a straight edge which contacts with theplane bottom surface of the notch. It will be seen that the shaft or in 89, together with the 'bar 89", can be reely swung about the axis of the centers. B means of the screw 74 and the hand wliieel. 75 the gage 89 can be moved axially, and this movement is effected in one way or the other as required to enable the straight edge o'f theV bar 89d to lie flat against the conical surface vof the gage 89a. When this adjustment has been made, the surface-89". of thegage occupies exactly the position which is to be afterward occupied bythe surface .i/*I of the wheel, the surface of the gage at 4the bottom, if extended, intersecting the axis of the centers.`

The gage 89" having been thus positioned, the dressing mechanism is moved to its Bolts 89, 89 extendingthe devices described so that the tool con.

tacts with the surface 89", as shown in Fig.

In the original construction of the machine the dressing tool has been mounted to ,move at an angle to the wheel axis, which angle is the same as that of the gage surface S9". Therefore, when the dressing tool is adjusted to engage the `said surface, it is in position to properly dress the wheel. After the dressing tool has been thus adjusted the gage 89a is removed and the wheel 1 put in place.e No further adjustment of the dressing tool takes place and the wheel is moved up to the tool in order to effect whatever dressing is necessary- The dressing tool will wear slightly as the result of its engagement with the wheel, and it will be understood that after wear has taken g lace the tool can be readjusted in the -way a ready described, making use of the 'ga e 89a.

nder some circumstances it may be desirable to remove one cutter holder and substitute another. These cutter holders may vary somewhat in construction with the result that the distance between the cutter axis and the top of the carriage 22 may vary. Inasmuch as the axis of the cutter must intersect the line of engagement between the wheel face and the cutter faces, it Will be seen that the position of the wheel and also of the dressing tool must be changed for a cutter holder of different height. These changesl in adjustment may be effect'- ed by adjusting the gage 89 in'the way already described.

The machine preferably includes, means whereby water may be delivered to thegrinding wheel; For this purpose I provide a pump 90 adapted to be driven by a belt wheel 91. A discharge pipe 92 leads from the pump and from the pipe water can be led to the Wheel by any usual or preferred means, such means' not being shown in the drawings. The carriage 22 is provided with a 'eripheral flange 93 which -serves to coll-ect t e Water discharged from the Wheel. The flange 93 is interrupted at 94 to pei'- niit the water to fiow downward onto the turntable 25, which is provided with a peripheral flange 95. A drain pipe 96 extends downward from the turntable 25, thus conducting yvater to a trough 97 which is mounted on the main frame. The knee 8 is also provided with a peripheral flange, thus serving to collect water which may fall on the knee. From the knee the water is discharged through a spout 97a into the trough 97. This trough'serves to conduct -the water to a reservoir in the interior of the main frame,which is not shown. FromA this reservoir the water is withdrawn by the pump 90 and returned to 'the wheel.

In operation, the cutter to be ground is mounted in the usual Way, as shown inFig. 6. If necessary the carriage 22 is moved to bring the cutter into the proper general relationship to the wheel, The turntable 25 is turned to an angle corresponding to the inclination of the cutting faces and the proper gears 48 and y51 are selected to effect turning at the reqinred rate. The two stops t0 are properly set in accordance with the position and length of the cutter. By means of the worm Wheel 69 and the worm 68, the cutter is turned angularly, if necessary, to bring the faces into proper relation with the wheel.

Then by means of the crank 38 the table 19 and the cutter are moved back and forth to effect grinding of one tooth. After one tooth has been ground, the cutter is indexed and another tooth ground, this being repeated until all the teeth have been ground.

Cutters of various diameters must be ground and the machine can be readily adiusted to accommodate such cutters by raising or lowering the knee 8 and the cutter holder carried thereby. As before explained, this adjustment does not interfere with `the intersection of the cutter axis with the line of contact between the conical grinding face and the cutter faces.

Fig. 6 shows the effect of the adjustment of the cutter holder for cutters of different diameters. The cutter A is shown in full lines in operative relation with the grinding wheel. A larger cutter is indicated by the dot-and-dash circle A', it being observed that the centers of both of the cutters are in line with the surface of the Wheel. If cutters with different degrees of inclination are met with, the machine can be adjusted accordingly by turning the turntable 25 and the attached parts about the vertical pivotal i axis. This adjustn'ient does not in any way grinding with the cutter axis` interfere with the intersection last above refel-red to. i

The wheel can be dressed from time` to time by means of the dressing tool 8(). This tool has a normallylixed operative position and no adjustment of the tool is required. The wheel itself is bodily moved up to the tool so as to maintain the grinding surface always inthe same position.

In preliminarily adjusting the machine, the dressingtool can be moved vto bring it into the correct position to bring about the before mentioned intersection' of the line of lf it should be necessary at any time to remove the cutter holder and substitute another one with a different elevation, the dressing tool could be adjusted to adapt the conical grinding surface of the wheel to the new position of the cutter axis.

`When the machine is to be used for grind ing cutters with straight plane faces, the turntable 25 is adjusted to 'bring the cutter on the disk.

thereof such as would oc'cur if the table 19 were to be moved on the saddle.

I have described the construction and operation of the `machine in connection with cutters having the front faces of their teeth exactly radial. Frequently, however, cutters are made with the front faces of the teeth undercut, that is, arranged so that instead of being radial they are spaced away from radial lines, as shown for instance at B in Fig. 13,. The `machine embodying my invention is equally well adapted for .grinding cutters ofv this type. The dressing tool is set in the Wa already described and the grinding wheel 1s dressed in the usual manner. Then, after swinging the dressing tool out of operative position, the wheel is moved axially outward to the position shown in Fig. 13, being then ready to engage the undercut faces of the cutter teeth and grind them in the way already described in connection with the cutters with definite predetermined amount corresponding tothe desired amount of undercut. In

.order that the amount of lwheel movement may be accurately determined, I' perferably provide a graduated disk 98 which is mounted on the outer part of the screw 74. Mounted on the slide 73 is an indicator 99 adapted to coperate with the graiiluations The graduations are such that the operator, after dressing the Wheel in its normal position, can move it outward to any predetermined distance, whichl distance is measured by the disk griuluations in connection with the pointer. Preferably, in order that the readings may start from Zero, the disk yis capable of turning on the' screw. A nut 10() is provided for locking the disk to the screw after adjustment. In operation, the operator first dresses the wheel, moving it, as required for this purpose.I Then the disk 98 is adjusted to bring the zero mark thereon opposite the pointer 99. The disk is locked in place by means. of thenut 100 and chine embodying the invention can be used for grinding such cutters by substituting a different, preferably, cylindrical, wheel, such as indicated at 101 in Fig; 14. The cutter is mounted on the centers in the usual way and is brought into engagement with the wheel by raising the knee and all of the parts carried thereby. If the cutter has straight teeth parallel with the axis, it can be moved back and forth underneath the wheel by moving the carriage 22. If the teeth are helical, the cutter can be turned during grinding by means of the turning devices already described. It will be under- Stood that the proper gears 48 and 51 are selected to effect turning at the rate cor res onding to the inclination of the teeth.

' f preferred, instead of using the gearing for turnjng the cutter, use can be made of a stop 2 which is adapted to engage the front faces of the teeth. As the cutter is moved longitudinally it can be manually turned to hold the front face of the tooth being ground in engagement with the stop.

What I claim is: l

1. The combination in a cutter grinding machine, of a grinding wheel rotatable about a horizontal axis and having a convex conical grinding face, a cutter holder having its axis intersecting and perpendicular to an element of the conical surface of the said grinding face, the said holder serving to present the front faces of the cutter teeth to the said grinding face, and means for effecting relative adjustment between the wheel and the cutter holder along linesparallel to the aforesaid element of the said conical surface. j

2. The combination in a cutter grinding machine, of a rotatable 'grindin wheel having a convex conical grinding ace, a cutter holder serving to present the `front faces of the cutter teeth to the said grinding face, the holder being adjustable about a pivotal axis perpendicular to the wheel axis, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the line of enga ement of the grinding face with the tooth aces. v

3. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, a cutter holder serving to present the front faces of the cutter teeth to the said grinding face, means upon which the holder is mounted for adjustment about a pivotal axis perpendicii- `lar to the wheel axis, and means for bodily adjusting the cutter holder and the pivotal mounting means therefor-toward or from lines parallel to the line of the grinding facewith the the wheel alon engagement o tooth faces.

4. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, a cutter holder having its axis intersecting per-f4 5 The'combination in a cutter grinding-` machine, of a rotatable grinding wheel having a convex conical grinding face, a cutter holder having its axisintersecting andper pendicular to an element of the conical surface of the said grindin face, the said holder serving to resent t e front faces of the cutter teeth to e said grinding face and bein-g' adjustable about a pivotal axis intersecting the cutter axis, and means for efefecting relative adjustment between the wheel and the lpivotal axis of said cutter holder along linesl element of thevsaid conical surface.

6.v The combination in machine, of a rotatable `indin wheei having a convex conical grinding ace, a cutter holder having its axis intersecting'and perpendicular to an element of the conical surface ofthe said grinding face, the said holder serving to present the frontl faces of th'e cutter teeth to the said grinding face and being adjustable about a, pivotal axis perpendicular to and intersecting the wheel axis and alsointersecting the aforesaid element parallel to the aforesaid a cutter grinding' of the said conical surface, and means forI effecting relative adjustment between the wheel and .the cutter holder along lines parallel to thesaid element.

7. The combination in a cutter grinding machine, of a rotatable grindin wheel having a convex conical grinding ace, a cutter holder having its axis inteisecting and per pendicular to an element of the conical surface of the said grinding facethe said holder serving to presentthe front faces of the cutter teeth to the said grindin face and being adjustable about a pivota axis intersecting the wheel axis. and also intersecting the iisv aforesaid element ofthe Said conical surface,

pendicular to an element of the conical sua-f 125 face of the said grinding, face, the sauf holder serving to present the front faces of the cutter teeth 'tehe said grindin and being adjusta iibout a pivota` axis perpendicular to and intersecting'both the face.

means for effecting holder serving to present the front faces of" the cutter teeth to the said grinding face and being adjustable about av pivotal axis interacting both the cutter axis and the wheel s and also intersecting the Laforesaid eleentof the said conical surface, and means i or effecting relative adjustment between the! f f 10. lhecombuiation in a cutter grinding holder along` lines parallel to the said ele- 1` machine, of ay rotatable grinding Wheel hav- 26 ing a convex conical grinding face, a cutter @holder having its axis intersecting` and pery iendicular to an element of the conical surlace of the said grinding face, the said holder serving to present the front faces of the cutter teeth to the'said grinding face and being adjustable about a pivotal axls perpenllicular tov and intersecting both the cutter axis and the wheel axis and also intersecting the aforesaid element ofthe said conical surface, and means for "bodily adjusting the cutter holder toward or from the wheel along lines parallel. to the said element.

lL The combination in a cutter grinding machine, of a rotatable grindin Wheel having a convex conical grinding ace, a cutter holder having .its axis intersecting and perL pendioular to an element of the conical sur face of the aid grinding face, the said holder serving to present the front faces of the cutter teeth to the said grinding ,ce and being adjustable about a pivotal airis intersecting both, the cutter axis and the wheel axis and also intersecting the aforesaid element of the fsaid conical surface7 and means for adjusting the pivotal axis of .said cutter holder toward said element.

12. The combination in a cutter grinding machine, of a rotatable grindin wheel hav-` i a convex conical grinding ace, a cutter ho der having its axis intersecting and per "pendicular to an element of the conical sur 'face of the said grinding face, the said holder being movable longitudinally of the `cutter axis and serving to present the front faces of t utter teeth to the said grinding face, .mean ed for ad'ustnicnt'about a pivotal a'xis per'- pei'u'liculisu' and intersecting both the out ter axis and the a'heelfaxis and also inter tive adju 'ment between the wheel and wheel and thepivotal axis of said cutterI r `from the Wheel along lines parallel to the non which the holder is mountmace sccting the afmesaid element of the said conical surface, means for turning the cutter about its axis in 'proportion to the said longitudinal movement to effect the grindingof helicoidal cutting faces, and means for effecting relative adjustment betwen the wheel and the cutter holder along lines parallel to the said element. v

13. The combination in a cutter grindingr machine, of a rotatable grinding wheel having a convex conicalgrindingr face, a cutter holder having its axis ix'itersccting and pcrj'iendioula r to an element of the conical surface of the said grinding face, the said holder being movable longitudinally of the cutter axis and serving to present the front faces machine, of a rotatable grinding wheel liaving a convex conical grinding face, a cutter holder having its ax1s lntersecting and perpendicular to an element of the conical surface of the said grinding face, the said holder being movable longitudinally of the cutter axis and. serving to present the front faces of the cutter teeth to the said grinding face, means upon which the holder is mounted for adjustment about a pivotal axis perpendicular to and intersecting both the cutter exis and the `Wheel axis and" also inter secting the aforesaid element of the said conical surface, means for turning thc cutter about its axis in proportion to the said'longitudinal movement to effect the grinding of helicoidal cutting faces, means for changing the rate of turning to conform to cutters with different degrees 4of inclination, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the said element.

l5, Thecombination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face. a cutter holder having its axis at an angle to the of the cutter teeth `to the said grinding face,

rinding face with the cutter axis, and means j or effecting relative adjustment between the iso wheel and the cutter holder along lines parallel to the aforesaid element of the said l conical surface.

16. The combination in va cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, a cutterV holder havin its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, means for bodily adjusting the wheel longitudinally ot' its axis to cause the perpendicular intersection of an element of the conical surface of the said grinding face with the cutter axis, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the aforesaid element of the said conical surface.

17. The combination in a cutter grinding machine, of a rotatable grinding wheel having a grinding face at" an angle to the wheel axis, a cutter holder having its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to thesaid grinding tace, means tor effecting relativev adjustment between the wheel .ind the cutter holder longitudinalljiv of the wneel axis to cause an element ot the surface. of the said grinding Vtace to perpendicularly intersect the cutter. axis or to lie at a distance therefrom, and means tor determining the yrelation between thc saidr clement and the said axis. l

18. The combination in a cutter grinding machine. of a rotatable grinding wheel having a convex conical grinding face1 a cutter holder having its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, means for eliecting relative adjustment between the wheel and the cutter holder longitudinally oi' the wheel axis to cause an element of the conical surface of the said grinding face to perpendicularly intersect the cutter axis or 'to lie at a distance thcreliri'un, means 'tor determining the relation between the said element andthe said axis, and means for eil'ecting relative adjustment between the. wheel and the cutter holder along lines parallel to the aforesaid element. of the said conical surface.

19. The combination in a cutter grinding machine, of a rotatable grinding wheel hai'- ing a lgrinding face at an angle to thcl wheell axis, a `cutter holder having its axis at an angle to the wheel axis. the said holder serving tol present the iront faces of the cutter teeth to the said grinding i'ace, means for effecting relative. adjustment hc- `tween the wheel and the entier holder longitudinally of the wheel axis to cause an elcment of thc surface of' the said grinding face to lie at a distance i'roni 'the cutter cause an element ot the `sui-tace of the said grinding tace to lie at a distance from the cutter axis, and means for measuring the sail distance, the said means including a graduated disk carried by the screw.

2l. The. coinliinatioi'i in a cutter grinding ninijrliine, of a rotatable grinding wheel having a convex conical grinding face, a cutter holder haring its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth toy the said grinding tace, means to adjust said holder about an axisy normal to the axis of the cutter, a stop adapted to engage the wheel at a point so positioned that an element of the conical surface of the said grinding face will perpendicularly intersect thc cutter axis, andn'ieans for effecting relative adjustment` between the wheel and the axis ol said cutter holder along lilies parallel to the aforesaid element ot the said conical surface. l

22. The combination in a cutter grinding machine, ol" a rotatable grinding wheel having a grinding face at an angle to the wheel axisx a cutter holder having its axis at an angle to the wheel axis, the said holder serving to present thel Vfront faces of the cutter teeth to the said grinding face. means l'or ettectiiig relative adjustment between the wheel and the cutter holder longitudi- :allay oi' the wheel axis, a stop adapted to engage the wheel at a point so positioned that an clement of the surface of the said grinding i'acc will perpendicularly intersect the cutter axis. and means :For measuring an)Y relative longitudinal adjustment beyond the position determined by the said stop.

2:5. 'llic combination in a cutter grinding machine. of a rotatable grinding vwheel haring a grinding l'ace at an angle to the wheel axis. a cutter holder having its axis at an angle to the whcel axis, the said helder serving to present ,the Jfront faces of the cutter teeth to the said grinding face, and a dressing lool'adapted to engage the wheel and movable along a normally fixed line so positioned that an element of the 'surface o'll the said grinding tace after dressing will ]icrpendiciilarly intersect the cutter axis..

24. The combination in a cutter grinding machine. oi' ii rotatable grinding wheel having a grinding vface at an angle tothe wheel` axis, a cutter holder having its axis at an angle to the wheel axis, the said holder serving to present the front face of the cutter -teethto the-said grinding face, means to faces of the cutter teeth to the said grindin j `l grinding face after dressing in hoflder having its axis at an face and being adjustable about a pivota axis perpendicular to and intersecting the cutter axis, and a dressing tool adapted to engage the wheel along a normally fixed line so positioned that an element of the surface of the said grinding face after dressin will perpendicularl intersect the cutter axis and also intersect t e pivotal axis. i

26r The combination in a cutter grinding machine, of a rotatable grindin wheel hava convex conical grinding ace, a cutter angle to the wheel axis,rthe saidliolder serving to present the front faces of the cutter teeth to the said grinding face, and a dressing tool ada ted to engage the wheel along a normal y fixed 'line-so ositioned that an' element of the, conical) surface of the said grinding face after dressing will dicularly intersect the cutter axis.

27. The combination in a cutter grinding machine, of a rotatable grinding wheel havperpenin a convex conical rindin v face a cutter4 holder having itsl axis at an angle to the wheel axis, the saidholder serving to present the front faces of the cutter teeth to the said grinding face,` means to adjust said wheel in a direction parallel to its axis, and a dressing tool adapted to engage thewheel along a normally fixed line so ositioned that an element of the conical sur ace of the said will perpendicularl intersect the cutter axis.

28. 1T e combination in a cutter grinding machine, of a rotatable grindin wheel having a convex conical grinding ace, a cutter holder having itsaxis at an angle to the wheel axis, the said holder serving to resent the front faces of the cutter teeth to t e said grinding face and being adjustable'about a pivotal axis perpendicular to and intersecting the cutter axis, and a dressing tool ada ted to engage the Wheel along a normally fixed line so positioned that an ele,- ment of the conical surface of the said grinding face after dressing will perpendicularly v i 15,2oe

intersect the4 cutter axis and also intersect the` pivotal axis. Y

29. The combination in a cutter grinding machine, of a rotatable grindin wheel vhaving a convex conical grinding ace a cutter holder lia-ving its axls at an angle to the wheel axis, the said holder serving to resent the front faces of the cutter teeth to t esaid grinding face, a dressing tool adapted to engage the` wheel along a normally fixed line so positioned that an element of the conical surface of the said rinding face after dressing will perpendicularly intersect the cutter axis, and means for effecting relative adjustment between the wheel and the cutter holder alon `lines parallel to the aforesaid element o the said conical surface.

30. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, a cutter holder having its axis at an angle to the wheel axis the said holder serving to resent the front faces of the cutter teeth to tie said grinding face, means to adjust said holder 'about an axis normal to the axis of the cutter, a dressing tool adapted to engage the ivhe'el along a tioned that lin-element of the conical surface of the said grinding perpendicularly intersect the cutter axis, and means for effecting relative adjustment between the wheel and the axis of said cutter holder along lines parallel to the aforesaid element of the said conical surface.

31. The combination in a cutter grinding machine, of a rotatable grindin ing a convex conical grinding fl' holder having its axis at an angle to the wheel axis, the said holder serving to )resent the front faces of the cutter teeth to t e said grinding face and 'being adjustable about a pivotal axis perpendicular to and intersecting the cutter axis, a dressing tool ada )ted to engage the wheel along a. normally fixed face after dressing will u wheel havace, a cutter normally fixed lline so posiioo after dressing will perpendicu'larly intersect the cutter axis and also intersectthe pivotal axis, and means for effecting relative adjustnient between the wheel and the cutter holder along lines parallel to the vaforesaid element of the said conical surface. Y

32. The combination in a cutter grinding machine2 of airotatable grinding wheel having a. grinding face at an angle to the wheel axis, a cutter holder havingy its axis at an angle to the wheel axis, the said holder servingr to present the front faces of the cutter teeth to the said grindingface, a dressing tool adapted to engage the wheel along a normally fixed line s positioned that an element of the surface of the said grinding face after dressing will pcrpcndcu-larly intersectthe cutter axis, means for adjusting the wheel longitudinally of its axis to bring to the wheel axis, the said holder serving,

to present the front faces of the cutter teet 1 4to the said grinding face, and a dressing tool ada ted to engage the wheel along a nor-` mal y lixed horizontal line so positioned that an element of the conical surface ot the-said rinding face after dressing will perpendicuiiirly intersect the cutter axis.

34. The combination in a cutter grinding machine, of a rotatable grinding wheel havinfr a convex conical grinding face, a cutter hotlder having its axis -a-t an angle to the wheel axis, the said holder serving to present the front 'faces of the cutter teeth to the said ygrinding face, and a dressing tool adapted to engage the-wheel along a Vnormally fixed line so positioned that an element otl the conical surface of the said grinding face after dressing will perpendicular-ly intersect the cutter axis, the dressing tool being inovably mounted so that it may be moved out of operative position when not in use.

35. The combination in a. cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, a cutter holder having its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face,- a dressing tool adapted to engage the wheel along a normally fixed line, and means for adjusting both the wheel and the dressing tool bodily along lines parallel with the wheel axis to bring about the perpendicular intersection of an element of the conical surface of the said'grinding face with the cutter axis.

Y 36. The combination in a cutter grinding machine. of a rotatably grinding wheel having a grinding tace at an angle to the wheel axis. Va cutter holder having its axis at an angle to the wheel axis. the said holder serving to present the .front faces of the cutter teeth to the said grinding `tace, :i dressing tool adapted to engage the wheel along a straight line. means for adjusting the dressing tool bodily along lines parallel with the wheel axis. anda gage adapted to be so locatcd that thc dressing tool when brought into contact with it will be in position to ldress the wheel so as to bring about the perpendicular intersection ot' an clement of the surface ot' the said grinding face with thev cutter axis.,

37. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, a cutter holder having its axis at an angle to the ,wheel axis, the said holder serving to present tlie front faces ot the cutter teeth to the said grinding face, a dressing tool adapted to engage the wheel along a straight line,

means for adjusting the dressing tool bodily along lines parallel with the wheel axis, and a gage adapted to be so located that the dressing tool when brought into contact with it will be in position to dress the wheel so as to bring about the perpendicular in.- tersection of an element ot' the conical szirface of the said grinding wiiii the cutter axis.

38. The combination in a cutter h machine, of a rotatable spindle. a grinding wheel on the spindle having a grinding face at an angle to the wheel axis. a cutter holder having its axis at an angle to the wheel axis. the said holder serving to present the 'fronty faces oiE the cutter teeth to the said grinding tace. a dressing tool. adapted to engage the wheel along a normally fixed line. means for adjusting'the dressing tool bodily along lines parallel with the wheel axis. and a gage adapted to be placed on the wheel spindle approximately in the position normally occupied by the wheel. the said gage to be so located and shaped that the dressing tool when brought into contact with it will be in position to dress the wheel so as to bring about the perpendicular intersection of anelement of the surface otl the said face with the cutter axis.

39. The combination in a cutter machine, of a rotatable spindle, a

grinding grinding grinding sis ico

wheel on the spindle having a con Vex conical grinding face. a cutter holder having its axis at an angle to the wheel axis. the said holder serving to pi'esent the front faces of the cutter teeth to the. said grinding face, a gage adapted to be placed on the spindle approximately in the position uoi'niall)r occupied by the wheel. the gage having a coni'cx conical sui-tace similar to that ot the wheel. a gage clement including a bar adapted to be positioned with a si raight edge surface thereof passing through the'nornial lint` of the cutter axis. means for moving the spindle longitudinally to adjust the conical surface ot the gage into line contact with the straight edge surface ot' the bar. :i wheel dressing tool adapted to contact with the gage. and incans t'or bodiliY adjusting the tool to bring it into position for movement along the. conical surface ot the gage after the gage has been adjusted as bet'orc stated.

ln tel-itiinonjv wlicrcof.` l hereto atlix in v signature. 

